Embodiments of the disclosure described herein relate to a memory device, and more particularly, relate to a method for a host device to control a storage device and a memory system including the host device and the storage device.
Mobile electronic devices such as digital cameras, MP3 players, cellular phones, smart phones, and tablet PCs are being widely used. Such mobile electronic devices use a nonvolatile memory device such as a flash memory as a medium for storing data. The nonvolatile memory device retains data stored therein even at power-off and has low-power and high-integration characteristics.
In the nonvolatile memory device, data retention characteristics may influence data integrity. For the flash memory device, charges (or electrons) stored in a floating gate or charge trap layer are leaked due to various causes to the outside thereof. For example, charges (or electrons) stored in a floating gate or charge trap layer are leaked through various fail mechanisms such as thermal ionic emission and charge diffusion through a defective insulating layer, ion impurities, and lapse of time. The leakage of charges causes a decrease in a threshold voltage of a memory cell. In contrast, various stresses cause an increase in a threshold voltage of a memory cell. An issue according to a change of a threshold voltage of a memory cell is called “retention problem”.
Accordingly, it is required to have a technique for preventing the reliability from being lowered due to charge leakage and the like.